Thermal Insulation Layer System

Abstract

In order to improve the resistance of heat insulation layers, in particular under the stresses due to high surface temperatures and temperature transients which are typical of gas turbines, a thermal insulation layer system which has a first main side which is provided for arrangement adjoining a component to be protected thermally and a second main side which is provided for arrangement adjoining a hot environment is proposed. The thermal insulation layer system has sections having different coefficients of thermal expansion.

1 .- 9 . (canceled) 
   
   
       10 . A thermal insulation layer system having sections with different coefficients of thermal expansion, comprising:
 a first main side arranged on a component to be given thermal protection; and   a second main side arranged adjoining a hot environment,   wherein a first section of the thermal insulation layer system which adjoins the component to be given thermal protection features a first coefficient of thermal expansion adapted to a coefficient of thermal expansion of the component, and   at least one further section of the thermal insulating layer system that features a smaller coefficient of thermal expansion than the first coefficient of thermal expansion.   
   
   
       11 . The thermal insulation layer system as claimed in  claim 10 , wherein the further section adjoins the second main side and has the smallest coefficient of thermal expansion of the thermal insulation layer system. 
   
   
       12 . The thermal insulation layer system as claimed in  claim 11 , wherein the smaller coefficient of thermal expansion of the further section adjoining the second main side is selected such that expansions occurring in typical operating conditions on the second main side lie in a specified range. 
   
   
       13 . The thermal insulation layer system as claimed in  claim 12 , wherein the layer system is a composite of a first thermal insulation layer that faces the component to be given thermal protection, and a second thermal insulation layer which faces the hot environment. 
   
   
       14 . The thermal insulation layer system as claimed in  claim 13 , wherein the first thermal insulation layer has a coefficient of thermal expansion of approximately 1.0·10 −5 K −1 . 
   
   
       15 . The thermal insulation layer system as claimed in  claim 13 , wherein the second thermal insulation layer has a coefficient of thermal expansion of approximately 8.0·10 −6 K −1 . 
   
   
       16 . The thermal insulation layer system as claimed in  claim 13 , wherein the layer system material is selected from the groups consisting of: 7YSZ/LA2Hf2O7, 7YSZ/BaZrO3, and 7YSZ/LaYbO3,
 where 7YSZ=Zirconium oxide, stabilized with 7% by weight % Yttrium oxide, and   where the first value designating the material of the first thermal insulation layer and the second value the material of the second thermal insulation layer.   
   
   
       17 . The thermal insulation layer system as claimed in  claim 16 , wherein the first and the second thermal insulation layers are joined to each other by a plasma spray method.